1. Field of the Invention
The present invention relates to mechanical fasteners and to electronic sensors for detecting failure of mechanical components, and particularly to a bolt tension monitoring system for transmitting signals identifying measured tension, power for and actuation of the system being provided through radio frequency power harvesting.
2. Description of the Related Art
Bolted joints are found in a wide range of structures and machines, and improperly tightened bolts, or loosened bolts, may severely compromise the safety and structural integrity of a joint. Insufficient pre-loading tension is a common cause of bolted joint failure. Similarly, due to the stresses a structure or machine undergoes in its lifetime, bolts can easily become loosened over time. Insufficient tension in the bolt, even if it was properly tightened at the time of construction, can also cause joint failure.
Given that most structures and machines use hundreds or thousands of bolts in their construction, it is impractical to regularly manually test the tension of each bolt. Bolts are often hidden from view or are otherwise inaccessible once a structure or machine is fully constructed. Thus, it would be desirable to provide a remote monitoring system that could measure the tension in a bolt, throughout its lifetime, and also provide accurate identification and location information for that bolt if a loss of tension is detected.
Thus, a bolt tension monitoring system solving the aforementioned problems is desired.